Onychocytic Matricoma Presenting as Longitudinal Melanonychia in a Skin of Color Patient

Gabriella Alvarez; Connie Kha; M Angelica Selim; Amber Fresco

doi:10.1159/000530470

Onychocytic Matricoma Presenting as Longitudinal Melanonychia in a Skin of Color Patient

Skin Appendage Disord. 2023 Aug;9(4):296-299. doi: 10.1159/000530470. Epub 2023 Jun 2.

Authors

Gabriella Alvarez¹, Connie Kha², M Angelica Selim^{2

3}, Amber Fresco²

Affiliations

¹ School of Medicine, Duke University, Durham, NC, USA.
² Department of Dermatology, Duke University Hospital, Durham, NC, USA.
³ Department of Pathology, Duke University Hospital, Durham, NC, USA.

PMID: 37564690
PMCID: PMC10410067 (available on 2024-08-01)
DOI: 10.1159/000530470

Abstract

Introduction: Onychocytic matricoma (OCM) is a benign acanthoma of the nail matrix that presents with longitudinal melanonychia and nail thickening. Only 18 previously reported cases of OCM are in the literature since it was first described in 2012.

Case presentation: The purpose of this case report was to report a unique presentation of OCM in the toenail of a Black patient as well as to review the clinical presentation, histologic features, and management of this rare entity. Previously described cases presented on the fingernails and were predominantly in white males.

Conclusion: OCM is a benign entity that may mimic a nail unit melanoma or squamous cell carcinoma especially when pachyonychia is present. Despite some clinical clues to suggest a diagnosis of OCM, a nail matrix biopsy is often required to rule out malignancy.

Keywords: Melanonychia; Onychocytic matricoma; Skin of color; Toenail.

Grants and funding

The authors received no funding.